ECT sensor No. 1

Disconnect the negative battery terminal. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION .)
Drain the engine coolant. (See ENGINE COOLANT REPLACEMENT .)
Lift up the vehicle.
Remove the front under cover No. 2. (See FRONT UNDER COVER NO. 2 REMOVAL/INSTALLATION .)
Disconnect the ECT sensor connector.
Remove the ECT sensor No. 1 using the SST.

Fig 1: ECT Sensor No. 1 With Torque Specification
Courtesy of MAZDA MOTORS CORP.
Install in the reverse order of removal.
Refill the engine coolant. (See ENGINE COOLANT REPLACEMENT .)